title: Electrochemical biosensor for detection of adenosine based on structure-switching aptamer and amplification with reporter probe DNA modified Au nanoparticles.
abstract: In the present study, an electrochemical sensing strategy for highly sensitive detection of small molecules was developed based on switching structures of aptamers from DNA/DNA duplex to DNA/target complex. A gold electrode was first modified with gold nanoparticles (AuNPs), and thiolated capture probe was immobilized onto the electrode via sulfur-gold affinity. Then, a "sandwich-type" strategy was employed, which involved a linker DNA containing antiadenosine aptamer sequence and reporter DNA loaded on AuNPs. In the presence of adenosine, the aptamer part bound with adenosine and folded to the complex structure. As a result, the reporter probes together with AuNPs were released into solution and reduced a decrease in peak current. With the enhancement effect of AuNPs, a detection limit as low as 1.8 x 10(-10) M for adenosine was achieved. The sensor exhibited excellent selectivity against other nucleosides and could be used to detect adenosine from real human serum samples.
authors.affiliation: Key Laboratory of Eco-chemical Engineering, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, China. shushzhang@126.com
authors.forename: Shusheng
authors.initials: S
authors.lastname: Zhang
authors.forename: Jianping
authors.initials: J
authors.lastname: Xia
authors.forename: Xuemei
authors.initials: X
authors.lastname: Li
mesh_terms: D000241:Adenosine / Q000032:analysis* / Q000378:metabolism; D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D015342:DNA Probes / Q000235:genetics / Q000378:metabolism*; D004563:Electrochemistry; D004566:Electrodes; D005260:Female; D006046:Gold / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010710:Phosphates / Q000737:chemistry; D011247:Pregnancy; D012428:Ruthenium / Q000737:chemistry; D012680:Sensitivity and Specificity; D055672:Static Electricity
chemical_list: D052157:Aptamers, Nucleotide; D015342:DNA Probes; D009942:Organometallic Compounds; D010710:Phosphates; D006046:Gold; D012428:Ruthenium; D000241:Adenosine